The European Commission does allow a legal entity or organisation to submit two or more project proposals under the same Call topic.
However, if two or more projects from the same organisation have been successful after proposal evaluation, the proposed budgets will have to be reviewed in order to avoid double funding. Therefore, as long as same costs under all projects are not declared twice, an organisation can participate in more than one project.
If two successful projects have overlapping personnel, activities and/or equipment, their costs will be covered by the first project’s budget proposal and removed from the second.
Moreover, as the organisation competes with itself under the same Call, project partners might request an “exclusivity and confidentiality agreement” prior to submitting the proposal. All changes in projects’ budgets have to be fully disclosed with the rest of the consortium. It should be checked that they are in compliance with the terms of the Consortium Agreement.
Be aware, however, that the second project can still be rejected during grant preparation, if a review of budget leads to a substantial change in the proposal.
Notwithstanding, not all Horizon 2020 funding programmes allow for multiple proposals.